Williams, ranked No. 1, will play four-time runner-up Maria Sharapova for the title on Saturday.

Williams was at her best before a near-capacity crowd for the final match on Thursday night, and she broke the tournament record for victories by a woman. She's 60-7; Steffi Graf went 59-6.

Williams had struggled in her previous two matches but played almost error-free tennis in the semifinal, using her superior power to keep Radwanska pinned deep and on the run. They played for 37 minutes and 55 points before Radwanska won a game.

Radwanska, who also lost to Williams in last year's Wimbledon final, fell to 1-11 against No. 1 players.

Serena will face four-time runner-up Maria Sharapova, who has advanced to another Key Biscayne final by beating Jelena Jankovic 6-2, 6-1 at the Sony Open.

With a victory Saturday, the No. 3-seeded Sharapova would plug one of the few holes in her resume. She completed a career Grand Slam by winning the French Open last year but has never won Key Biscayne.

On a sunny, mild afternoon on Thursday, Sharapova won the first 10 points against the No. 22-seeded Jankovic and hardly let up from there. Sharapova committed only 10 unforced errors from the baseline in 88 points while breaking serve six times.